Control method for image acquisition device, control device therefor, and storage medium

ABSTRACT

Embodiments of the present invention provide a control method for an image acquisition device, a control device therefor, and a storage medium, relate to the field of the image acquisition device, and aim to realize synchronization of an operation timing signal of the image acquisition device and an external trigger signal. The method comprises: receiving image data acquired by the image acquisition device; analyzing the image data, obtaining an image timing according to an analysis result, and determining a frame synchronization signal of the image data output by the image acquisition device according to the image timing; determining a phase offset between the frame synchronization signal and a preset trigger signal; and adjusting a phase of a control signal based on the phase offset, wherein the control signal is configured for adjusting an operation timing of the image acquisition device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure claims priority to Chinese Patent Application No.202010787944.3, titled “CONTROL METHOD FOR IMAGE ACQUISITION DEVICE,CONTROL APPARATUS THEREOF AND CONTROL DEVICE THEREFOR, AND STORAGEMEDIUM”, filed on Aug. 7, 2020, the content of which is incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to the field of an image acquisitiondevice, and in particular, to a control method for an image acquisitiondevice, a control device therefor, and a storage medium.

BACKGROUND

Image acquisition devices have been widely used in home scenes orworkplaces, but some image acquisition devices without trigger (singleframe trigger) function (such as some automotive grade image acquisitiondevices available from SONY corporation) cannot be synchronized with anexternal trigger signal in general, wherein the external trigger signalis an external signal received by a reserved port of the imageacquisition device, which results in edge triggering or level triggeringon the image acquisition device and thus forms the external triggersignal. Meanwhile, simultaneous exposure is also impossible when aplurality of image acquisition devices are linked.

In summary, an operation timing signal of the image acquisition devicecannot be synchronized with the external trigger signal in the priorart.

SUMMARY

Embodiments of the present invention provide a control method for animage acquisition device, a control means thereof and a control devicetherefor, and a storage medium, and aim to realize synchronization of anoperation timing signal of the image acquisition device and an externaltrigger signal.

In a first aspect, an embodiment of the present invention provides acontrol method for an image acquisition device comprising:

receiving image data acquired by the image acquisition device;

analyzing the image data, obtaining image timing according to ananalysis result, and determining a frame synchronization signal of theimage data output by the image acquisition device according to the imagetiming;

determining a phase offset between the frame synchronization signal anda preset trigger signal; and

adjusting a phase of a control signal based on the phase offset, whereinthe control signal is configured for adjusting an operation timing ofthe image acquisition device.

The control method for the image acquisition device provided by theembodiment of the present invention comprises: firstly receiving imagedata acquired by the image acquisition device, analyzing the image data,obtaining an image timing according to an analysis result, anddetermining a frame synchronization signal of the image data output bythe image acquisition device according to the image timing; thendetermining a phase offset between the frame synchronization signal anda preset trigger signal; and finally adjusting a phase of a controlsignal based on the phase offset, wherein the control signal isconfigured for adjusting an operation timing of the image acquisitiondevice. Compared with the prior art, the control method is characterizedby that the triggering signal is compared with the image output timingof the image acquisition device to calculate the phase difference, thetiming control of the image acquisition device is performed according tothe comparison result, and the image acquisition device is provided witha timing adjusting signal pin so that the operation timing of the imageacquisition device can be adjusted by adjusting the control signal, andthe timing synchronization of the image output timing and the triggersignal is finally realized.

In one possible embodiment, adjusting the phase of the control signalbased on the phase offset comprises:

adjusting the phase of the control signal using the phase offset whendetermining that image data output time of the image acquisition deviceis coincident with exposure start time of the image acquisition device.

In one possible embodiment, adjusting the phase of the control signalbased on the phase offset further comprises:

determining a waiting duration between image data output time of theimage acquisition device and exposure start time of the imageacquisition device when determining that the image data output time isnot coincident with the exposure start time; and

adjusting the phase of the control signal using the phase offset, andadvancing trigger time of the control signal by the waiting duration.

In one possible embodiment, adjusting the phase of the control signalusing the phase offset comprises:

dividing the phase offset into a plurality of shifts smaller than apreset shift threshold, wherein the preset shift threshold is themaximum phase shift allowed by single adjustment; and

adjusting the phase of the control signal in a gradually approachingmanner based on the plurality of shifts smaller than the preset shiftthreshold.

In one possible embodiment, when a plurality of image acquisitiondevices are connected simultaneously and exposure durations of theplurality of image acquisition devices are different, the method furthercomprises:

receiving image brightness values sent by the plurality of imageacquisition devices;

determining a uniform exposure duration of the plurality of imageacquisition devices based on the image brightness values of theplurality of image acquisition devices;

determining a brightness gain of a target image acquisition device basedon the uniform exposure duration and an image brightness value of thetarget image acquisition device, wherein the target image acquisitiondevice is any one of the plurality of image acquisition devices; and

configuring the brightness gain of the target image acquisition deviceto the target image acquisition device, and controlling the target imageacquisition device to expose in the uniform exposure duration.

When a plurality of image acquisition devices are connectedsimultaneously and exposure durations of the plurality of imageacquisition devices are different, the control method for the imageacquisition device provided by the embodiment of the present inventionfurther comprises: firstly receiving image brightness values sent by theplurality of image acquisition devices; then determining a uniformexposure duration of the plurality of image acquisition devices based onthe image brightness values of the plurality of image acquisitiondevices, and determining a brightness gain of a target image acquisitiondevice based on the uniform exposure duration and an image brightnessvalue of the target image acquisition device, wherein the target imageacquisition device is any one of the plurality of image acquisitiondevices; and finally configuring the brightness gain of the target imageacquisition device to the target image acquisition device, andcontrolling the target image acquisition device to expose in the uniformexposure duration. Compared with the prior art, when a plurality ofimage acquisition devices are connected simultaneously, the controlmethod of the present invention solves the problem that exposure canonly start simultaneously while cannot end simultaneously due todifferent exposure durations of the plurality of image acquisitiondevices, and has advantages that synchronous exposure of the pluralityof image acquisition devices is realized by configuring respectivebrightness gain and uniform exposure duration for each image acquisitiondevice.

In one possible implementation, determining the brightness gain of thetarget image acquisition device based on the uniform exposure durationand the image brightness value of the target image acquisition devicecomprises:

performing a weighted sum on the image brightness values of the targetimage acquisition devices according to brightness weights preset by thetarget image acquisition devices, and dividing the weighted sum by a sumof brightness weights of the plurality of image acquisition devices todetermine an average brightness value of the plurality of imageacquisition device; and

determining a brightness difference value between the image brightnessvalue of the target image acquisition device and the average brightnessvalue as the brightness gain of the target image acquisition device.

In a second aspect, an embodiment of the present invention provides acontrol means of an image acquisition device comprising:

a reception unit for receiving image data acquired by the imageacquisition device;

an analysis unit for analyzing the image data, obtaining image timingaccording to an analysis result, and determining a frame synchronizationsignal of the image data output by the image acquisition deviceaccording to the image timing;

a determination unit for determining a phase offset between the framesynchronization signal and a preset trigger signal; and

a control unit for adjusting a phase of a control signal based on thephase offset, wherein the control signal is configured for adjusting anoperation timing of the image acquisition device.

In one possible embodiment, the control unit is specifically configuredfor:

adjusting the phase of the control signal using the phase offset whendetermining that image data output time of the image acquisition deviceis coincident with exposure start time of the image acquisition device.

In one possible embodiment, the control unit is further specificallyconfigured for:

determining a waiting duration between image data output time of theimage acquisition device and exposure start time of the imageacquisition device when determining that the image data output time isnot coincident with the exposure start time; and

adjusting the phase of the control signal using the phase offset, andadvancing trigger time of the control signal by the waiting duration.

In one possible embodiment, when a plurality of image acquisitiondevices are connected simultaneously and exposure durations of theplurality of image acquisition devices are different, the control meanscomprises a processing unit configured for:

receiving image brightness values sent by the plurality of imageacquisition devices;

determining a uniform exposure duration of the plurality of imageacquisition devices based on the image brightness values of theplurality of image acquisition devices;

determining a brightness gain of a target image acquisition device basedon the uniform exposure duration and an image brightness value of thetarget image acquisition device, wherein the target image acquisitiondevice is any one of the plurality of image acquisition devices; and

configuring the brightness gain of the target image acquisition deviceto the target image acquisition device, and controlling the target imageacquisition device to expose in the uniform exposure duration.

In one possible embodiment, the processing unit is specificallyconfigured for:

performing a weighted sum on the image brightness values of the targetimage acquisition devices according to brightness weights preset by thetarget image acquisition devices, and dividing the weighted sum by a sumof brightness weights of the plurality of image acquisition devices todetermine an average brightness value of the plurality of imageacquisition device; and

determining a brightness difference value between the image brightnessvalue of the target image acquisition device and the average brightnessvalue as the brightness gain of the target image acquisition device.

In a third aspect, an embodiment of the present invention furtherprovides a control system for an image acquisition device comprising amain control module, and the image acquisition device, a cache module, astorage module, an interface module and a power module connected withthe main control module, wherein

the image acquisition device is configured for sending output image datato the main control module;

the main control module is configured for analyzing received image data,obtaining an image timing according to an analysis result, determining aframe synchronization signal of the image data output by the imageacquisition device according to the image timing, determining a phaseoffset between the frame synchronization signal and a preset triggersignal, and adjusting a phase of a control signal based on the phaseoffset, wherein the control signal is configured for adjusting anoperation timing of the image acquisition device;

the cache module is configured for caching boot codes applied in themain control module;

the storage module is configured for storing the image data processed inthe main control module;

the interface module is configured for providing network communicationfor the main control module; and

the power module is configured for supplying power to the imageacquisition device and the main control module.

In one possible implementation, the control system further comprises:

a serializer and a deserializer connected between the image acquisitiondevice and the main control module, wherein

the serializer is configured for performing parallel-serial conversionon the image data output by the image acquisition device to generateserial data and sending the serial data to the deserializer, and thedeserializer is configured for receiving the serial data sent by theserializer and performing serial-parallel conversion, and sending theconverted image data to the main control module.

In a fourth aspect, an embodiment of the present invention furtherprovides a control device for an image acquisition device comprising:

at least one processor, at least one memory, and computer programinstructions stored in the memory that, when executed by the processor,implement the control method for an image acquisition device provided bythe first aspect of the embodiment of the present invention.

In a fifth aspect, an embodiment of the present invention furtherprovides a computer-readable storage medium having computer programinstructions stored thereon that, when executed by a processor, enablethe control device of an image acquisition device to implement thecontrol method of an image acquisition device provided in the firstaspect of the embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of exemplaryembodiments of the present invention will be easily understood byreading the following detailed description with reference to theaccompanying drawings. In the accompanying drawings, several embodimentsof the present invention are illustrated by way of example and notlimitation, wherein

FIG. 1 is a schematic structural diagram of a control system for animage acquisition device according to an embodiment of the presentinvention;

FIG. 2 is a schematic structural diagram of a control system for anotherimage acquisition device according to an embodiment of the presentinvention;

FIG. 3 is a signal timing diagram of a frame synchronization signal anda horizontal synchronization signal according to an embodiment of thepresent invention;

FIG. 4 is a signal timing diagram of another frame synchronizationsignal and a horizontal synchronization signal according to anembodiment of the present invention;

FIG. 5 is a signal timing diagram of a frame synchronization signal anda trigger signal according to an embodiment of the present invention;

FIG. 6 is a schematic diagram illustrating adjustment of a phase of acontrol signal according to an embodiment of the present invention;

FIG. 7 is a schematic diagram illustrating adjustment of a phase ofanother control signal according to an embodiment of the presentinvention;

FIG. 8 is a schematic structural diagram of another control system foran image acquisition device according to an embodiment of the presentinvention;

FIG. 9 is a schematic flowchart of a control method for an imageacquisition device according to an embodiment of the present invention;

FIG. 10 is a schematic structural diagram of a control means of an imageacquisition device according to an embodiment of the present invention;and

FIG. 11 is a schematic structural diagram of a control device for animage acquisition device according to an embodiment of the presentinvention.

DETAILED DESCRIPTION

In view of the fact that image acquisition devices without trigger(single frame trigger) function (such as some automotive grade imageacquisition devices available from SONY corporation) cannot besynchronized with an external trigger signal in the prior art, anembodiment of the present invention provides a control scheme for animage acquisition device, where a Field Programmable Gate Array (FPGA)is configured to control an interface timing of an image acquisitiondevice without trigger function, and at the same time, the FPGA monitorsthe trigger signal, compares the trigger signal with an image outputtiming of the image acquisition device to calculate a phase difference,and performs timing control for the image acquisition device accordingto a comparison result, thereby achieving a function similar to thetrigger function. The following describes a control method for an imageacquisition device according to an embodiment of the present inventionin detail with reference to the accompanying drawings and specificembodiments.

Further, the trigger signal must have a fixed frequency, and the framerate of the image acquisition device is an integral multiple of thefrequency, for example, the image acquisition device has a frame rate of60 FPS, and the trigger signal has a stable frequency of 20 Hz. Theprecondition can be easily met in the fields of automatic driving,robots and the like, so the scheme provided in the embodiment of thepresent invention can also be generally applied in the fields ofautomatic driving, robots and the like.

FIG. 1 exemplarily illustrates a schematic structural diagram of acontrol system for an image acquisition device according to anembodiment of the present invention. As shown in FIG. 1, the systemcomprises a main control module 11, a cache module 12, a storage module13, an image acquisition device 14, a power module 15, and an interfacemodule 16.

The main control module is configured for receiving image data acquiredby the image acquisition device and it may be a Field Programmable GateArray (FPGA) or a System on Chip (SOC) with programmable logic; thecache module is configured for caching data when the system runs and itmay be a Double Data Rate (DDR) memory; the storage module is configuredfor storing boot codes and it may be a serial peripheral interface flash(SPI flash), a Secure Digital Card (SD Card), a NOR flash, a NAND flashor an Embedded Multi Media Card (EMMC); the image acquisition device isconfigured for acquiring image data and an interface thereof may be aMobile Industry Processor Interface (MIPI), a High-Speed Pixel Interface(HiSpi), or a Digital Video Port (DVP); the interface module may be aGigabit Media Independent Interface (GMII) or a Reduced Gigabit MediaIndependent Interface (RGMII); there is no limitation for these thingsin the present invention.

FIG. 2 exemplarily illustrates a schematic structural diagram of anothersynchronization system for an image acquisition device according to anembodiment of the present invention. As shown in FIG. 2, the systemcomprises a main control module 21, a cache module 22, a storage module23, an image acquisition device 24, a power module 25, an interfacemodule 26, a deserializer 27, and a serializer 28.

An interface of the deserializer and the serializer may be an FPD LINKIII interface (a bidirectional control interface), a GMSL (GigabitMultimedia Serial Link)/GMSL2 interface or a V-BY-ONE interface (adigital interface developed specifically for image transmission), andthere is no limitation for this in the present invention.

Further, what the image acquisition device does comprises exposing aphotosensitive unit, and performing AD conversion on the photosensitiveunit and outputting after some other processing; determination can onlybe made according to the timing of the received image because the maincontrol module can only passively receive image data output by the imageacquisition device, and there is a fixed (deviation, if present, is inns level and can be ignored) time difference between the timing of theimage received by the main control module and the operation timing ofthe image acquisition device so that the timing in the image acquisitiondevice can be reversely deduced. Images output by either the MIPIinterface or the DVP interface, or other interfaces, can recover thetiming containing Vertical Synchronization (vsync) signal and HorizontalSynchronization (hsync) signal, where the vsync can be used to representthe start of a frame of image and the hsync can be used to indicate thestart of a row of images.

FIG. 3 is a signal timing diagram of a frame synchronization signal anda horizontal synchronization signal according to an embodiment of thepresent invention, and FIG. 4 is a signal timing diagram of anotherframe synchronization signal and a horizontal synchronization signalaccording to an embodiment of the present invention. Since there is afixed time difference between a frame synchronization signal analyzed inthe main control module and an internal operation timing of an imageacquisition device, a timing of the image acquisition device can bedetermined by the frame synchronization signal.

Further, the frame synchronization signal plus a certain offset canrepresent the internal operation timing of the image acquisition device,therefore only the phase difference between the trigger (single frametrigger) signal and the frame synchronization signal needs to bemonitored. As shown in FIG. 5, there is a fixed time difference betweenthe trigger signal and the vsync signal, and the trigger signal isconsistent with the internal operation timing signal of the imageacquisition device.

Further, three schemes are provided below for how to control an imageacquisition device and thereby to implement trigger synchronization, anddetailed description is provided below with reference to specificembodiments.

Embodiment I

In one possible embodiment, some image acquisition devices have a timingadjustment signal frame synchronization (fsync) pin, which is forfine-tuning the operation timings of the image acquisition devices andthereby achieving synchronous output of data of multiple imageacquisition devices. Because the control of data output of the imageacquisition device will indirectly control the exposure timing of theimage acquisition device, the timing of the fsync signal can beaccurately controlled by the main control module, thereby graduallyachieving a function similar to trigger.

It should be noted that, signal interaction may be directly performedbetween the image acquisition device and the main control module, ordata of the image acquisition device may be sent to the main controlmodule through the serializer and the deserializer, and meanwhile, themain control module sends a control signal to the image acquisitiondevice through the deserializer and the serializer, and there is nolimitation for this in the present invention.

When the fsync signal changes within a certain range, the imageacquisition device can adjust its own operation timing to form a certainphase relationship with the fsync signal to keep synchronization.Therefore, a vsync signal analyzed from an image output by the imageacquisition device can be compared with a trigger signal based on thischaracteristic, and the phase offset between the vsync signal and thetrigger signal is determined according to the comparison result, therebydetermining the phase change of the fsync signal, controlling the outputof the fsync signal and finally realizing the control of the imagetiming of the image acquisition device.

As shown in FIG. 6, the change range of the fsync signal received bysome of the image acquisition devices cannot be too large, otherwise,the image acquisition device may operate abnormally, and therefore, agradual approaching manner may be adopted for such image acquisitiondevices. In each frame, a certain value of phase is adjusted each time,and the phase cannot exceed the allowable change range of the imageacquisition device. The fsync signal is synchronized with trigger signalby gradual adjustments of multiple frames. The trigger signal in FIG. 6has a fixed frequency, and the alignment of the vsync signal with thetrigger signal is controlled by adjusting the position of the fsyncsignal. Therefore, the image timing of the image acquisition devicewithout trigger function can be synchronized with the external triggersignal with a fixed frequency, which comprises the following steps inspecific implementation:

S1, receiving and analyzing, by a main control module, image data sentby the image acquisition device, obtaining an image timing anddetermining a vsync signal;

S2, comparing the vsync signal with the trigger signal, and determininga phase offset between the vsync signal and the trigger signal accordingto the comparison result; and

S3, adjusting the phase of the fsync signal according to the phaseoffset determined in S2, and adjusting, by the image acquisition device,its own operation timing to form a certain phase relationship with thefsync signal to keep synchronization; therefore adjusting the phase ofthe fsync signal is equivalent to adjusting the operation timing of theimage acquisition device.

In one possible embodiment, during the phase adjustment of the fsync, amaximum phase shift for a single adjustment of the fsync signal ispreset by the image acquisition device, and the fsync signal graduallyapproaches based on the maximum phase shift until the adjustment of thephase offset is completed.

Therefore, the phase change of the fsync signal can cause the change ofthe operation timing inside the image acquisition device. When the maincontrol module receives the image data sent by the image acquisitiondevice again, the vsync signal also changes with the change of theoperation timing since there is a fixed time difference between thevsync signal obtained by analyzing the image data and the internaloperation timing of the image acquisition device, and the vsync signalis compared with the trigger signal again and the fsync signal isadjusted again according to the comparison result until the fsync signalis synchronized with the trigger signal, that is, the image timing ofthe image acquisition device is synchronized with the external triggersignal with a fixed frequency.

Embodiment II

In one possible embodiment, also for an image acquisition device withouttrigger function, the synchronization between the image timing and thetrigger signal is realized after the synchronization in the Embodiment Iis completed, that is, the trigger signal arrives, and the imageacquisition device outputs the image data within an acceptable timedifference; however, for some image acquisition devices, the image dataoutput does not represent that the image acquisition device startsexposure because an SHS (a waiting duration) is present between thestart of frame and the start of exposure, and the image acquisitiondevice starts image output but does not start exposure when the triggersignal arrives so that there is a time difference between the triggertime of the trigger signal and the exposure start time.

In specific implementation, as shown in FIG. 7, the frame rate persecond is preset, and the duration of one frame can be obtained. Theexposure duration is also preset in each frame, the exposure duration ofthe current image acquisition device can be obtained by an automaticexposure module, and the SHS time is obtained by subtracting theexposure duration from the duration of one frame. The frequency and thephase of the fsync signal can be obtained by the method in theEmbodiment I, and then the fsync signal can be advanced by SHS duration;the image acquisition device triggers one frame in advance according tothe fsync signal and starts exposure after the SHS duration passed, theexposure duration is consistent with the trigger signal, and thesynchronization of image exposure and the trigger signal is achieved. Inspecific implementation, the following steps may be comprised:

S1, receiving and analyzing, by a main control module, image data sentby the image acquisition device, obtaining an image timing anddetermining a vsync signal;

S2, comparing the vsync signal with the trigger signal, and determininga phase offset between the vsync signal and the trigger signal accordingto the comparison result;

S3, obtaining, by the main control module, the exposure duration of theimage acquisition device, obtaining the duration of one frame accordingto the preset frame rate, and determining SHS duration by calculatingthe difference between these two;

in specific implementation, the frame rate of the image acquisitiondevice is preset, and the duration of one frame can be obtained; theexposure duration is also preset in each frame, so that the duration ofone frame and the exposure duration of the current image acquisitiondevice can be obtained by the main control module, and the SHS time isthe difference between these two; and

S4, adjusting the phase of the control signal using the phase offsetaccording to the phase offset determined in S2 and the SHS durationdetermined in S3, and advancing the trigger time of the adjusted controlsignal by the SHS duration.

Embodiment III

FIG. 8 is a schematic structural diagram of another control system foran image acquisition device according to an embodiment of the presentinvention. In various machine vision applications, a plurality of imageacquisition devices are required to simultaneously start exposure andsimultaneously end exposure; however, in actual application, it ispossible to start exposure simultaneously upon the arrival of thetrigger signal due to the necessity of starting the automatic exposurealgorithm, but ending the exposure simultaneously cannot be achieved.For example, in an autonomous vehicle, the image acquisition devicesfacing the front of the vehicle is exposed to stronger light, and theimage acquisition devices facing two sides of the vehicle are exposed toweaker light. In this case, longer exposure duration is set for theimage acquisition devices on two sides of the vehicle, and shorterexposure duration is set for the image acquisition devices in the frontof the vehicle. Thus, if the same fsync signal is used, some imageacquisition devices will end exposure early, and some later. Therefore,an embodiment of the present invention provides a linkage scheme of aplurality of image acquisition devices, which can realize that theplurality of image acquisition devices start exposure simultaneously andend exposure simultaneously.

In specific implementation, the linkage scheme comprises the followingsteps:

S1, setting a brightness weight for each image acquisition device;

in specific implementation, the brightness weight of the imageacquisition device can be set according to the light intensity aroundthe image acquisition device, for example, the brightness weight of theimage acquisition device in the front of the vehicle can be set to 1 ifthe light intensity around the image acquisition device is strong andthe light is sufficient; the brightness weight of the image acquisitiondevices on two sides of the vehicle can be set to 0.8 if the lightintensity around the image acquisition devices are weak;

S2, dynamically sending at each frame, by the linked image acquisitiondevices, the image brightness value counted by the linked imageacquisition devices to a main control module;

S3, determining, by the main control module, an appropriate exposureduration according to the image brightness values of all the imageacquisition devices, that is, the exposure durations of the linked imageacquisition devices are the same;

in specific implementation, overall brightness values corresponding to aplurality of different scenes can be preset, and each overall brightnessvalue corresponds to a preset exposure duration;

further, the overall brightness value may be a brightness value for aspecific image acquisition device, or may be an average brightness valueof the values for a plurality of image acquisition devices, and there isno limitation for this in the present invention;

S4, determining a brightness gain of each image acquisition deviceaccording to the image brightness value of each image acquisition deviceand the corresponding brightness weight;

in specific implementation, the weighted sum may be performed on theimage brightness values of the plurality of image acquisition devicesbased on the brightness weights corresponding to the image brightnessvalues, then an average brightness value is obtained by dividing theweighted sum by a sum of brightness weights of the plurality of imageacquisition devices, and the image brightness value of each imageacquisition device is compared with the average brightness value toobtain a brightness difference value of each image acquisition device,which is determined as the brightness gain of each image acquisitiondevice;

S5, sending the exposure duration to all linked image acquisitiondevices, and sending different brightness gains to the correspondingimage acquisition device; and

S6, in the case that the exposure durations of the plurality of imageacquisition devices are the same, for the image acquisition devicereceiving weak light, the same exposure duration can be realized byincreasing the brightness gain, that is, the brightness gain is adjustedto compensate the exposure duration; meanwhile, for the imageacquisition device receiving strong light, the same exposure durationcan be realized by reducing the brightness gain, that is, the brightnessgain is adjusted to reduce the exposure duration.

In one possible embodiment, in order to ensure that better image qualitycan be realized with the premise that a plurality of image acquisitiondevices can start exposure simultaneously and end exposuresimultaneously, at least one third of the field of view of each of theimage acquisition devices linked together is required to be overlappedwith one another.

As shown in FIG. 9, an embodiment of the present invention provides acontrol method for an image acquisition device comprising:

Step 901, receiving image data acquired by the image acquisition device;

Step 902, analyzing the image data, obtaining image timing according toan analysis result, and determining a frame synchronization signal ofthe image data output by the image acquisition device according to theimage timing;

Step 903: determining a phase offset between the frame synchronizationsignal and a preset trigger signal; and

Step 904: adjusting a phase of a control signal based on the phaseoffset, wherein the control signal is configured for adjusting anoperation timing of the image acquisition device.

In one possible embodiment, adjusting the phase of the control signalbased on the phase offset comprises:

adjusting the phase of the control signal using the phase offset whendetermining that image data output time of the image acquisition deviceis coincident with exposure start time of the image acquisition device.

In one possible embodiment, adjusting the phase of the control signalbased on the phase offset further comprises:

determining a waiting duration between image data output time of theimage acquisition device and exposure start time of the imageacquisition device when determining that the image data output time isnot coincident with the exposure start time; and

adjusting the phase of the control signal using the phase offset, andadvancing trigger time of the control signal by the waiting duration.

In one possible embodiment, adjusting the phase of the control signalusing the phase offset comprises:

dividing the phase offset into a plurality of shifts smaller than apreset shift threshold, wherein the preset shift threshold is themaximum phase shift allowed by single adjustment; and

adjusting the phase of the control signal in a gradually approachingmanner based on the plurality of shifts smaller than the preset shiftthreshold.

In one possible embodiment, when a plurality of image acquisitiondevices are connected simultaneously and exposure durations of theplurality of image acquisition devices are different, the method furthercomprises:

receiving image brightness values sent by the plurality of imageacquisition devices;

determining a uniform exposure duration of the plurality of imageacquisition devices based on the image brightness values of theplurality of image acquisition devices;

determining a brightness gain of a target image acquisition device basedon the uniform exposure duration and an image brightness value of thetarget image acquisition device, wherein the target image acquisitiondevice is any one of the plurality of image acquisition devices; and

configuring the brightness gain of the target image acquisition deviceto the target image acquisition device, and controlling the target imageacquisition device to expose in the uniform exposure duration.

In one possible implementation, determining the brightness gain of thetarget image acquisition device based on the uniform exposure durationand the image brightness value of the target image acquisition devicecomprises:

performing a weighted sum on the image brightness values of the targetimage acquisition devices according to brightness weights preset by thetarget image acquisition devices, and dividing the weighted sum by a sumof brightness weights of the plurality of image acquisition devices todetermine an average brightness value of the plurality of imageacquisition device; and

determining a brightness difference value between the image brightnessvalue of the target image acquisition device and the average brightnessvalue as the brightness gain of the target image acquisition device.

As shown in FIG. 10, an embodiment of the present invention provides acontrol means of an image acquisition device comprising:

a reception unit 101 for receiving image data acquired by the imageacquisition device;

an analysis unit 102 for analyzing the image data, obtaining imagetiming according to an analysis result, and determining a framesynchronization signal of the image data output by the image acquisitiondevice according to the image timing;

a determination unit 103 for determining a phase offset between theframe synchronization signal and a preset trigger signal; and

a control unit 104 for adjusting a phase of a control signal based onthe phase offset, wherein the control signal is configured for adjustingan operation timing of the image acquisition device.

In one possible embodiment, the control unit 104 is specificallyconfigured for:

adjusting the phase of the control signal using the phase offset whendetermining that image data output time of the image acquisition deviceis coincident with exposure start time of the image acquisition device.

In one possible embodiment, the control unit 104 is further specificallyconfigured for:

determining a waiting duration between image data output time of theimage acquisition device and exposure start time of the imageacquisition device when determining that the image data output time isnot coincident with the exposure start time; and

adjusting the phase of the control signal using the phase offset, andadvancing trigger time of the control signal by the waiting duration.

In one possible embodiment, when a plurality of image acquisitiondevices are connected simultaneously and exposure durations of theplurality of image acquisition devices are different, the control meanscomprises a processing unit 105 configured for:

receiving image brightness values sent by the plurality of imageacquisition devices;

determining a uniform exposure duration of the plurality of imageacquisition devices based on the image brightness values of theplurality of image acquisition devices;

determining a brightness gain of a target image acquisition device basedon the uniform exposure duration and an image brightness value of thetarget image acquisition device, wherein the target image acquisitiondevice is any one of the plurality of image acquisition devices; and

configuring the brightness gain of the target image acquisition deviceto the target image acquisition device, and controlling the target imageacquisition device to expose in the uniform exposure duration.

In one possible embodiment, the processing unit 105 is specificallyconfigured for:

performing a weighted sum on the image brightness values of the targetimage acquisition devices according to brightness weights preset by thetarget image acquisition devices, and dividing the weighted sum by a sumof brightness weights of the plurality of image acquisition devices todetermine an average brightness value of the plurality of imageacquisition device; and

determining a brightness difference value between the image brightnessvalue of the target image acquisition device and the average brightnessvalue as the brightness gain of the target image acquisition device.

Based on the same conception of the embodiment of the present inventiondescribed above, an embodiment of the present invention further providesa control device for an image acquisition device.

An embodiment of the present invention further provides a control systemfor an image acquisition device comprising a main control module, andthe image acquisition device, a cache module, a storage module, aninterface module and a power module connected with the main controlmodule, wherein

the image acquisition device is configured for sending output image datato the main control module;

the main control module is configured for analyzing received image data,obtaining an image timing according to an analysis result, determining aframe synchronization signal of the image data output by the imageacquisition device according to the image timing, determining a phaseoffset between the frame synchronization signal and a preset triggersignal, and adjusting a phase of a control signal based on the phaseoffset, wherein the control signal is configured for adjusting anoperation timing of the image acquisition device;

the cache module is configured for caching boot codes applied in themain control module;

the storage module is configured for storing the image data processed inthe main control module;

the interface module is configured for providing network communicationfor the main control module; and

the power module is configured for supplying power to the imageacquisition device and the main control module.

In one possible implementation, the control system further comprises:

a serializer and a deserializer connected between the image acquisitiondevice and the main control module, wherein

the serializer is configured for performing parallel-serial conversionon the image data output by the image acquisition device to generateserial data and sending the serial data to the deserializer, and thedeserializer is configured for receiving the serial data sent by theserializer and performing serial-parallel conversion, and sending theconverted image data to the main control module.

As shown in FIG. 11, an embodiment of the present invention provides acontrol means 110 of an image acquisition device comprising:

at least one processor 1101, at least one memory 1102, and computerprogram instructions stored in the memory that, when executed by theprocessor 1101, implement the control method for an image acquisitiondevice provided by the embodiment of the present invention.

In an exemplary embodiment, provided is a storage medium comprisinginstructions, for example, a memory 1102 comprising instructions thatcan be executed by a processor 1101 of a control device of an imageacquisition device to implement the above method.

Optionally, the storage medium may be a non-transitory computer-readablestorage medium, for example, the non-transitory computer-readablestorage medium may be a ROM, a Random Access Memory (RAM), a CD-ROM, amagnetic tape, a floppy disk, an optical data storage device, and thelike.

It should be appreciated by those skilled in the art that embodiments ofthe present application may be provided as a method, a system, or acomputer program product. Accordingly, the present application may takethe forms of a hardware-only embodiment, a software-only embodiment oran embodiment combining software and hardware. Furthermore, the presentapplication may take the form of a computer program product implementedon one or more computer-usable storage media (including, but not limitedto, disk memory, CD-ROM, optical memory, and the like) containingcomputer-usable program codes.

The present application is described with reference to flowcharts and/orblock diagrams of a method, a device (system), and a computer programproduct according to the present application. It will be understood thateach step and/or block of the flowcharts and/or block diagrams, and acombination of steps and/or blocks in the flowcharts and/or blockdiagrams, can be implemented by computer program instructions. Thesecomputer program instructions may be provided to a processor of ageneral-purpose computer, a dedicated computer, an embedded processor,or other programmable data processing device to produce a machine, suchthat the instructions executed by the processor of the computer or otherprogrammable data processing devices produce a means for implementingthe functions specified in one or more steps in the flowcharts and/orone or more blocks of block diagrams.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing devices to operate in a particular manner,such that the instructions stored in the computer-readable memoryproduce a product comprising an instruction means which implements thefunctions specified in one or more steps in the flowcharts and/or one ormore blocks of block diagrams.

These computer program instructions may also be loaded onto a computeror other programmable data processing devices to allow a series ofoperation steps to be performed on the computer or other programmableapparatus to produce a computer implemented process, such that theinstructions executed on the computer or other programmable devicesprovide steps for implementing the functions specified in one or moresteps in the flowcharts and/or one or more blocks of block diagrams.

It will be apparent to those skilled in the art that various changes andmodifications may be made to the present application without departingfrom the spirit and scope of the present application. Thus, if suchmodifications and variations of the present application fall within thescope of the claims of the present application and the equivalentsthereof, the present application is intended to include suchmodifications and variations as well.

What is claimed is:
 1. A method, comprising: receiving image dataacquired by an image acquisition device; analyzing the image data, toobtain an analysis result; obtaining an image timing according to theanalysis result; determining a frame synchronization signal with whichthe image acquisition device outputs the image data according to theimage timing; determining a phase offset between the framesynchronization signal and a preset trigger signal; and adjusting aphase of a control signal based on the phase offset.
 2. The methodaccording to claim 1, wherein the adjusting the phase of the controlsignal based on the phase offset comprises: adjusting the phase of thecontrol signal using the phase offset in response to image data outputtime of the image acquisition device being coincident with exposurestart time of the image acquisition device.
 3. The method according toclaim 2, wherein the adjusting the phase of the control signal using thephase offset comprises: dividing the phase offset into a plurality ofshifts smaller than a preset shift threshold, wherein the preset shiftthreshold is a maximum phase shift allowed by a single adjustment; andadjusting the phase of the control signal in a gradually approachingmanner based on the plurality of shifts.
 4. The method according toclaim 1, wherein the adjusting the phase of the control signal based onthe phase offset comprises: determining a waiting duration between imagedata output time of the image acquisition device and exposure start timeof the image acquisition device in response to the image data outputtime being not coincident with the exposure start time; adjusting thephase of the control signal using the phase offset; and advancingtrigger time of the control signal by the waiting duration.
 5. Themethod according to claim 4, wherein the adjusting the phase of thecontrol signal using the phase offset comprises: dividing the phaseoffset into a plurality of shifts smaller than a preset shift threshold,wherein the preset shift threshold is the maximum phase shift allowed bya single adjustment; and adjusting the phase of the control signal in agradually approaching manner based on the plurality of shifts.
 6. Themethod according to claim 1, further comprising: in response to theimage acquisition device comprising a plurality of image acquisitiondevices and exposure durations of the plurality of image acquisitiondevices being different with each other, receiving image brightnessvalues from the plurality of image acquisition devices; determining auniform exposure duration of the plurality of image acquisition devicesbased on the image brightness values; determining a brightness gain of atarget image acquisition device based on the uniform exposure durationand an image brightness value of the target image acquisition device,wherein the target image acquisition device is one of the plurality ofimage acquisition devices; configuring the target image acquisitiondevice with the brightness gain; and controlling the target imageacquisition device to expose in the uniform exposure duration.
 7. Themethod according to claim 6, wherein the determining the brightness gainof the target image acquisition device based on the uniform exposureduration and the image brightness value of the target image acquisitiondevice comprises: performing a weighted summation on the imagebrightness values of the image acquisition devices according tobrightness weights preset by the image acquisition devices, to obtain aweighted sum value; dividing the weighted sum value by a sum ofbrightness weights of the plurality of image acquisition devices todetermine an average brightness value of the plurality of imageacquisition device; and determining a brightness difference valuebetween the image brightness value of the target image acquisitiondevice and the average brightness value as the brightness gain of thetarget image acquisition device.
 8. A device, comprising: at least oneprocessor, at least one memory, and computer program instructions storedin the memory that, when executed by the processor, implement a methodcomprising: receiving image data acquired by an image acquisitiondevice; analyzing the image data, to obtain an analysis result;obtaining image timing according to the analysis result; determining aframe synchronization signal with which the image acquisition deviceoutputs the image data according to the image timing; determining aphase offset between the frame synchronization signal and a presettrigger signal; and adjusting a phase of a control signal based on thephase offset.
 9. The device according to claim 8, wherein the adjustingthe phase of the control signal based on the phase offset comprises:adjusting the phase of the control signal using the phase offset inresponse to image data output time of the image acquisition device beingcoincident with exposure start time of the image acquisition device. 10.The device according to claim 9, wherein the adjusting the phase of thecontrol signal using the phase offset comprises: dividing the phaseoffset into a plurality of shifts smaller than a preset shift threshold,wherein the preset shift threshold is a maximum phase shift allowed by asingle adjustment; and adjusting the phase of the control signal in agradually approaching manner based on the plurality of shifts.
 11. Thedevice according to claim 8, wherein the adjusting the phase of thecontrol signal based on the phase offset comprises: determining awaiting duration between image data output time of the image acquisitiondevice and exposure start time of the image acquisition device inresponse to the image data output time being not coincident with theexposure start time; adjusting the phase of the control signal using thephase offset; and advancing trigger time of the control signal by thewaiting duration.
 12. The device according to claim 11, wherein theadjusting the phase of the control signal using the phase offsetcomprises: dividing the phase offset into a plurality of shifts smallerthan a preset shift threshold, wherein the preset shift threshold is themaximum phase shift allowed by a single adjustment; and adjusting thephase of the control signal in a gradually approaching manner based onthe plurality of shifts.
 13. The device according to claim 8, whereinthe method further comprises: in response to the image acquisitiondevice comprising a plurality of image acquisition devices and exposuredurations of the plurality of image acquisition devices being differentwith each other, receiving image brightness values from the plurality ofimage acquisition devices; determining a uniform exposure duration ofthe plurality of image acquisition devices based on the image brightnessvalues; determining a brightness gain of a target image acquisitiondevice based on the uniform exposure duration and an image brightnessvalue of the target image acquisition device, wherein the target imageacquisition device is one of the plurality of image acquisition devices;configuring the target image acquisition device with the brightnessgain; and controlling the target image acquisition device to expose inthe uniform exposure duration.
 14. The device according to claim 13,wherein the determining the brightness gain of the target imageacquisition device based on the uniform exposure duration and the imagebrightness value of the target image acquisition device comprises:performing a weighted summation on the image brightness values of theimage acquisition devices according to brightness weights preset by theimage acquisition devices, to obtain a weighted sum value; dividing theweighted sum value by a sum of brightness weights of the plurality ofimage acquisition devices to determine an average brightness value ofthe plurality of image acquisition device; and determining a brightnessdifference value between the image brightness value of the target imageacquisition device and the average brightness value as the brightnessgain of the target image acquisition device.
 15. A computer-readablestorage medium having computer program instructions stored thereon that,when executed by a processor, implement a method comprising: receivingimage data acquired by an image acquisition device; analyzing the imagedata, to obtain an analysis result; obtaining image timing according tothe analysis result; determining a frame synchronization signal withwhich the image acquisition device outputs the image data according tothe image timing; determining a phase offset between the framesynchronization signal and a preset trigger signal; and adjusting aphase of a control signal based on the phase offset.
 16. Thecomputer-readable storage medium according to claim 15, wherein theadjusting the phase of the control signal based on the phase offsetcomprises: adjusting the phase of the control signal using the phaseoffset in response to image data output time of the image acquisitiondevice being coincident with exposure start time of the imageacquisition device.
 17. The computer-readable storage medium accordingto claim 15, wherein the adjusting the phase of the control signal basedon the phase offset comprises: determining a waiting duration betweenimage data output time of the image acquisition device and exposurestart time of the image acquisition device in response to the image dataoutput time being not coincident with the exposure start time; adjustingthe phase of the control signal using the phase offset; and advancingtrigger time of the control signal by the waiting duration.
 18. Thecomputer-readable storage medium according to claim 17, wherein theadjusting the phase of the control signal using the phase offsetcomprises: dividing the phase offset into a plurality of shifts smallerthan a preset shift threshold, wherein the preset shift threshold is themaximum phase shift allowed by single adjustment; and adjusting thephase of the control signal in a gradually approaching manner based onthe plurality of shifts.
 19. The computer-readable storage mediumaccording to claim 15, wherein the method further comprises: in responseto the image acquisition device comprising a plurality of imageacquisition devices and exposure durations of the plurality of imageacquisition devices being different with each other, receiving imagebrightness values from the plurality of image acquisition devices;determining a uniform exposure duration of the plurality of imageacquisition devices based on the image brightness values; determining abrightness gain of a target image acquisition device based on theuniform exposure duration and an image brightness value of the targetimage acquisition device, wherein the target image acquisition device isone of the plurality of image acquisition devices; configuring thetarget image acquisition device with the brightness gain; andcontrolling the target image acquisition device to expose in the uniformexposure duration.
 20. The computer-readable storage medium according toclaim 19, wherein the determining the brightness gain of the targetimage acquisition device based on the uniform exposure duration and theimage brightness value of the target image acquisition device comprises:performing a weighted summation on the image brightness values of theimage acquisition devices according to brightness weights preset by theimage acquisition devices, to obtain a weighted sum value; dividing theweighted sum value by a sum of brightness weights of the plurality ofimage acquisition devices to determine an average brightness value ofthe plurality of image acquisition device; and determining a brightnessdifference value between the image brightness value of the target imageacquisition device and the average brightness value as the brightnessgain of the target image acquisition device.